1. Field of the Invention
The invention relates to music and to musical instruments. More specifically, the invention relates to all types of wind instruments and especially to brasses and woodwinds having an air column contained therein that creates transverse sound waves when induced into longitudinal vibration.
2. Description of the Prior Art
In a music instrument having an air column, the shape of the air column determines the resonant frequencies that will be produced by the instrument. It is known that an abrupt change in the circular cross-section of a tube introduces increased impedance and that the effect of such a discontinuity is to introduce an inductance in series with the standing waves of the air column, thereby producing a reinforced response in the instrument.
U.S. Pat. No. 3,973,464 to Donald A. Novy discloses a piston valved brass-wind musical instrument having an exponentially offset series of reflective, eliptically constricted bore sections. The amounts of offset are based upon a percentage of the inside bore diameter taken at mid-bore length. This series of interferences, exponentially doubled at each piston's ports, creates an analogous impedance that significantly improves the response of the instrument, thereby making it easier to play and affording the player benefits of improved range, endurance, intonation and dynamic control.
While the noted patent imparts significant advantages to a piston valved instrument, it would be desirable to extend the benefits to other types of wind instruments, including non-valved instruments.
Further, an alternative technique of achieving these benefits would be desirable even in a piston valved instrument, in which it would be unnecessary to re-align the pistons.
To achieve the foregoing and other objects and in accordance with the purpose of the present invention, as embodied and broadly described herein, the acoustic coil and method of manufacture of this invention may comprise the following.